package com.hmdp.utils;

import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

@Component
public class RedisIdWorker {
    /**
     * 开始时间戳
     */
    private static final long BEGIN_TIMESTAMP = 1735689600L;
    /**
     * 序列号的位数
     */
    private static final long COUNT_BITS = 32;

    private StringRedisTemplate redisTemplate;

    public RedisIdWorker(StringRedisTemplate redisTemplate) {
        this.redisTemplate = redisTemplate;
    }

    public long nextId(String keyPrefix){
        // 1. 计算时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(java.time.ZoneOffset.UTC);
        long timestamp = nowSecond - BEGIN_TIMESTAMP;

        // 2. 计算序列号
        // 2.1 获取当前日期，精确到天
        String date =  now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        // 2.2 自增长
        long increment = redisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + date);

        // 3. 拼接
        return timestamp << COUNT_BITS | increment;
    }
}

